The pectoralis major is a powerful chest muscle that causes the arm to rotate inward and move closer to the body. It can also help move the arm forward or backward. The muscle originates from two points: the sternum (breastbone) and the clavicle (collarbone). These two sections of the muscle come together into the pectoralis major tendon, which is attached to the humerus bone of the upper arm, near the biceps tendon.
Injury to the pectoralis major tendon is relatively uncommon, but can result in significant disability in athletes.
The pectoralis major tendon is most commonly injured during an eccentric contraction – when the external force on the muscle is greater than the force that the muscle can generate – and when the arm is extended and externally (outwardly) rotated, such as when performing a bench press.
Bench pressing is the most common cause of injury, but other activities leading to injury include rugby, skiing, football, wrestling, hockey, and parachuting. Pectoralis major injuries typically occur in men aged 20 to 40, and have affected several New York Giants football players. The injury can result in pain in the chest and upper arm, weakness, and deformity of the chest and upper arm.
This injury can often be identified through a physical examination, as the muscle bulk and shape on the chest wall is visibly different on the injured side compared with the normal side. Bruising of the chest wall may also be apparent. These physical findings are often accompanied by pain when attempting to internally rotate and pull the arm to the side. If the injury is chronic, doctors may notice a decrease in muscle mass.
Surgery is usually required to repair pectoralis major injuries, except when there is a partial tear of the tendon, when there is a rupture of the center of the muscle, or in elderly patients. Athletes who injure the pectoralis major muscle usually desire a full return of strength to return to their sport. This is best accomplished with surgical repair. A study has shown that only 27 percent of athletes treated without surgery had an excellent result.
Surgical treatment involves an incision centered between the pectoralis major muscle and the deltoid muscles of the shoulder. The tendon can be re-attached to the bone by a variety of techniques. Occasionally, a tendon transplant is required to complete the repair, typically when the injury is chronic.
After surgery, patients are usually immobilized in a sling for three to six weeks. Gentle pendulum exercises are started during this period. Carefully instructed passive and active exercises are added over the following months, and light weight lifting is allowed at four months. Patients typically return to competitive activity after six months.
Injury to the pectoralis major tendon is relatively uncommon, but can result in significant disability in athletes